WEAR RESISTANCE OF POLIESTER- Al2O3 COMPOSITES

Plastik malzeme türleri günden güne artmakta ve bu malzemelerden farklı özellikler elde etmek için kompozitleri üretilmektedir. Kullanımı yaygın bir plastik türü olan polyestere, aşınma dayanımını arttırmak üzere farklı ağırlık oranlarında Al2O3 partikülleri takviye edilerek plastik matriksli partikül takviyeli kompozit malzemeler üretilmiştir. Üretilen kompozit malzemeler Pim-Disk modeli bir aşınma deney düzeneğinde aynı tribolojik şartlarda aşınma deneyine tabi tutulmuştur. Aynı tribolojik şartlar altında aşınma deneyleri yapılan Polyester-Al2O3 kompozitlerinin aşınma dayanımlarının, polyester içindeki Al2O3 oranının artışıyla yükseldiği belirlenmiştir. Aşınma dayanımı ile sertlik arasında bir ilişki belirlenememiştir. The varieties of plastic materials increase day by day and composites of these materials are produced to obtain different properties. Particule reinforced plastic matrix composite materials are produced by reinforcing different weight ratios. Al2O3 particules for increasing wear resistance of polyester, a common by used plastic material. The composite materials produced are subjected to wear experiment in a pin-on-disk model wear experiment setup for equal tribological conditions. It is found that wear resistance of Poliester-Al2O3 composites increase with the increase of Al2O3 ratio. No correlation could be detected between the wear resistance and hardness

AN INVESTIGATION ON THE PRECIPITATION HARDENING OF TIG WELDED 2024 ALUMINUM ALLOY

Bu çalışmada levha şeklinde üretilmiş olan 2024 alüminyum işlem alaşımı 600'lik V kaynak ağzı açılarak TIG kaynak yöntemi ile argon gazı altında ER4043 elektrot kullanılarak birleştirilmiştir. Kaynaklanmış örnekler 492±3 0C'de çözeltiye alınmış ve oda sıcaklığında su verilmiştir, daha sonra bir kısmı doğal yaşlandırılırken bir kısmı da 125 0C'de 22 saat ve 190 0C'de 8.5 saat yapay yaşlandırılmıştır. Kaynaklı örnekler çekme ve çentik darbe deneylerine tabi tutulmuştur. Kaynaklı bölgenin mikrosertliği ölçülüp içyapısı incelenmiştir. In this study, 2024 aluminum wrought alloy manufactured in the form of plates has been welded with TIG welding method under protecting argon gas by using ER4043 electrode as filler metal. The welding geometry is with 600 groove type. The specimens were solution heattreated under 492±3 0C and quenched in water at room temperature. Then, they were aged naturally and artificially. Artificial aging was performed at 125 0C for 22 hours and at 190 0C for 8,5 hours. Natural aging was performed at room temperature for one week. All welding specimens were subjected to tension and Charpy tests. Microhardness and microstructure of the welded specimens were determined

Joining of Powder Metal Parts with Steel Parts by Induction Sintering Method

Bu çalışmada, ST 37-2 çeliği üzerine bakır ve grafit içerikli demir tozu farklı basınçlarda preslenmiş, elde edilen parça indüksiyon ile ve karşılaştırma amaçlı olarak geleneksel sinterleme yöntemleri ile sinterlenerek, çelik ile toz metalden oluşan kademeli malzemeler üretilmiştir. Üretilen numunelere üç nokta eğme testi gerçekleştirilmiştir. Ayrıca numunelerin Rockwell - B sertlik değerleri ve mikro yapıları incelenmiştir.In this study, Fe based cupper and graphite included metal powder were pressed on ST 37-2 steel with different pressures. Obtained components were sintered with induction and conventional sintering methods and gradual parts were produced. Three point bending test were applied to produced samples. Also Rockwell-B hardness and microstructures of samples were investigated

The Effect of Polymer Type on the Thermal Stability and Mechanical Behavior of Blue Phase Cholesteric Liquid Crystal

Bu çalışma kapsamında, ilk olarak, mavi faz kolesterik sıvı kristal örnekleri hazırlanmıştır. Hazırlanan bu numuneler içerisine farklı konsantrasyonlarda ve farklı kimyasal yapılardaki çeşitli polimerler eklenerek UV (ultraviyole) ışık altında polimerizasyonları yapılmıştır. UV ışığının yoğunluğu, polimerizasyon süresi polimerizasyonun tamamlanması açısından oldukça önemli olduğu için polimerzasyon koşulları optimize edilmiştir. Polimerizasyonları tamamlanan numunelerin termal kararlılıkları, mekanik davranışları incelenmiştir. Polimerizasyon sonucunda incelenen numunelerde termal kararlılığın ve mekanik dayanıklılığın, kullanılan polimerin bir fonksiyonu olarak değiştiği görülmüştür.In this study, blue phase liquid crystal mixtures were formulated as a first step. These specimens were polymerized via UV (ultraviolet) light after the polymers with different functionality at the different concentrations were added into the blue phase liquid crystals mixtures. Polymerization conditions have been optimized since the intensity of the UV light is very important in completing the polymerization. The thermal stability and mechanical behavior of the polymerized samples were investigated. It has been observed that the thermal and mechanical stabilities of the samples changed as a function of the polymer used

INVESTIGATION OF DEFORMATION TEMPERATURES AND STRAIN RATE EFFECTS' ON THE MECHANICAL PROPERTIES OF Al 99.0

The effects of deformation temperature and strain rate to the mechanical properties of Aluminum (Al 99.0) were investigated by tensile experiment at different deformation temperatures and strain rate. At the end of investigation; it was determined that, with increasing deformation temperature, yield and tensile strenghts of the material decrease, strain rate and decrease of area increase, when plastic deformation exponent (n) decreases, strain rate accuracy exponent (m) increases. At a fixed temperature an increase in deformation speed increased all mechanical properties

Application of the Hall-Petch Relation to Microhardness Measurement on AA 1030, Cu, CuSn7, CuZn30 and 6114 Alloys

In this experimental study, the strip formed specimens made from aluminum alloy 1030, pure Cu, CuSn7, CuZn30 and low carbon steel 6114 were cold worked to different ratios. To be able to determine the microhardness values of the materials, the microhardness tests were applied. Grain sizes of the materials were determined by the Heyn method using metal microscope. The hardness of materials H, is dependent on the grain diameter, d, in a similar way as in the flow stress in the Hall-Petch relation: H=H0+KHd-1/2 where H0 and KH are constants. The microhardness of the materials is found to vary with the grain size according to the Hall-Petch equation with reasonable accuracy

Determination Of Yield Strenght of 2014 Aluminium Alloy under Aging Conditions by Means of Artifical Neural Networks Method

As known, 2XXX and 7XXX Aluminum process alloys can have high strength values by means of precipitation hardening heat treatment. Determination of the precipitation hardening conditions which can give the most suitable strength values of an alloy, requires numerous tests. But the results of this process which require long time and high cost can be obtained in a shorter time and at a lower cost with less data by means of Artificial Neural Networks method. Since this method is used, less number of experiments and therefore less data is needed. Then other values are found by means of Artificial Neural Networks method.In this study, Artificial Neural Networks were educated with yield strength values of 2014 Aluminum alloy obtained at different aging times and at 150, 190, 232, and 260 °C after taken into solution at 500 °C. Afterwards, yield strengths of alloy at different temperatures weredetermined by means of Artificial Neural Networks method